Wireless telecommunications systems utilize any of a variety of technologies and standards such as, for example, Global System for Mobile Communications (GSM); Code Division Multiple Access (CDMA); Time Division Multiple Access (TDMA); Frequency Division Multiple Access (FDMA); Personal Communications Service (PCS); and Advanced Mobile Phone Service (AMPS). Wireless telecommunications systems, both digital and analog, are composed of several distinct pieces of equipment and processors that are interconnected, each to carry out dedicated functions. The costs and complexity associated with the manufacture, maintenance and interface of such distinct equipment are relatively high.
The difficulties associated with interfacing distinct equipment can be illustrated with a GSM wireless telecommunications system. GSM has become the standard digital cellular phone service throughout Europe, Japan, Australia and elsewhere and is defined in specifications provided by the European Telecommunications Standards Institute (ETSI). The GSM specifications define discrete functionalities that carry out dedicated functions. These discrete functionalities have been implemented using discrete equipment that must be interfaced.
GSM wireless telecommunications systems may be separated into various subsections such as, among others, a Network Subsystem (NSS), a Base Station Subsystem (BSS) and an Operations and Maintenance Center (OMC). These subsections include such components as (a) a Base Station Controller (BSC); (b) a Base Transceiver Station (BTS); (c) a Mobile Switching Center (MSC); (d) a Visitor Location Register (VLR); (e) a Home Location Register (HLR); (f) an Authentication Center (AuC); (g) an Operations and Maintenance Center-Radio (OMC-R); and (h) an Operations and Maintenance Center-Switching (OMC-S). The implementation of these components as discrete equipment and processors is cumbersome, complex and expensive.
For example, the functionality of the AuC and HLR are often implemented using separate equipment and processors. This significantly increases overall system costs and interface complexity. Maintenance and operational expenses are also increased because of the need to maintain separate equipment.
Although the integration of discrete functionalities may solve many of the complexities and expenses associated with the implementation of discrete, dedicated equipment and processors, additional problems are presented. One such problem surrounds processor capacity and loading.
For example, in a GSM wireless telecommunications system, a subscriber unit is generally authenticated each time the subscriber unit requests service. Authentication involves the generation of three values, referred to as "triplets," using the AuC. The triplets include a Random Number (RAND), a Signed Response (SRES) and a Ciphering Key (Kc). Authentication uses a previously stored and encrypted Authentication Key (Ki), that is unique for each subscriber, and the RAND as inputs to complex algorithms to generate both SRES and Kc. The complex algorithms are mathematically intensive and require extensive processor power and capability. As a result, authentication can be unacceptably lengthy, even when using dedicated equipment, such as a dedicated authentication center, to perform such functions. The situation becomes even more problematic as various wireless telecommunications system functionality is integrated into the same equipment that is controlled by the same processor. This further loads the processor and exacerbates the authentication problem outlined above.